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Math Help - probability word problem help, please....

  1. #1
    Newbie JoanneMac's Avatar
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    Exclamation probability word problem help, please....

    Ok, I have 3 word problems dealing with probability that I need help with. So here they areWondering)

    1.Suppose a contest offers $1,000 to the person who can guess the winning 4 digit number. How many possibilities are there?

    2. Two marbles are drawn froma bag containing 6 white, 4 red, and 6 green marbles. Find the probability of both marbles being white.

    3. Suppose there are 10 items on a true-false test. The person taking the test does not read the questions; he just answers each question randomly. What is the probability of his guessing all answers correctly?

    Thanks in advance for any help!
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  2. #2
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    number 2

    Well number 2 is relatively easy you take the amount of white marbles 6 then put it over the total amount of marbles i.e 6+4+6 so u get 6/16(for the prob. that the first marble is white) then multiply that by 5/15(i.e. prob that second marble is white) then u get 17/24 for
    Quote Originally Posted by JoanneMac View Post
    Ok, I have 3 word problems dealing with probability that I need help with. So here they areWondering)

    1.Suppose a contest offers $1,000 to the person who can guess the winning 4 digit number. How many possibilities are there?

    2. Two marbles are drawn froma bag containing 6 white, 4 red, and 6 green marbles. Find the probability of both marbles being white.

    3. Suppose there are 10 items on a true-false test. The person taking the test does not read the questions; he just answers each question randomly. What is the probability of his guessing all answers correctly?

    Thanks in advance for any help!
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  3. #3
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    Number three i believe that u multiply his chances of getting each question correct i.e he has 1/2 chance of getting number one corect then 1/2 chance of getting number two correct so u end up with 1/2x by itself 10 times or 1/2^10 and u get an answer of 1/1024
    Quote Originally Posted by JoanneMac View Post
    Ok, I have 3 word problems dealing with probability that I need help with. So here they areWondering)

    1.Suppose a contest offers $1,000 to the person who can guess the winning 4 digit number. How many possibilities are there?

    2. Two marbles are drawn froma bag containing 6 white, 4 red, and 6 green marbles. Find the probability of both marbles being white.

    3. Suppose there are 10 items on a true-false test. The person taking the test does not read the questions; he just answers each question randomly. What is the probability of his guessing all answers correctly?

    Thanks in advance for any help!
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  4. #4
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    i think number one is just that the amount of possibilities are 9999
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  5. #5
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    Quote Originally Posted by adeshSB View Post
    i think number one is just that the amount of possibilities are 9999
    You mean(9)(9)(9)(9) = 9^4, right ....?
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  6. #6
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    Quote Originally Posted by JoanneMac View Post
    [snip]

    2. Two marbles are drawn froma bag containing 6 white, 4 red, and 6 green marbles. Find the probability of both marbles being white.

    [snip]
    Drawing a tree diagram is always a good idea for these sorts of questions.
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  7. #7
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    Quote Originally Posted by JoanneMac View Post
    Ok, I have 3 word problems dealing with probability that I need help with. So here they areWondering)

    1.Suppose a contest offers $1,000 to the person who can guess the winning 4 digit number. How many possibilities are there?

    2. Two marbles are drawn froma bag containing 6 white, 4 red, and 6 green marbles. Find the probability of both marbles being white.

    3. Suppose there are 10 items on a true-false test. The person taking the test does not read the questions; he just answers each question randomly. What is the probability of his guessing all answers correctly?

    Thanks in advance for any help!
    3. The chance of getting any one question right is 50%, or 0.5.

    The chance of getting all 10 right is (0.5)^10, or .0009765625. If we round this to .001, that means you have about one chance in a thousand of getting them all right, or 0.1%
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  8. #8
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    Quote Originally Posted by TheMasterMind View Post
    3. The chance of getting any one question right is 50%, or 0.5.

    The chance of getting all 10 right is (0.5)^10, or .0009765625. If we round this to .001, that means you have about one chance in a thousand of getting them all right, or 0.1%
    *Ahem* .... Which confirms reply #3 .....
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